Insulator construction



Jan. 17, 1939. R L. JENNER INSULATOR CONSTRUCTION Filed Oct. 7, 1937 4IISATTORNEYS or other supports for the insulators are not of uni- Patented Jan. 17, 1939 PATENT OFFICE INSULATOB CONSTRUCTION Ralph L. Jenner, Le Roy, N. Y., assignor to Lapp Insnlato ration of New York r Company, Inc., Le Roy, N. Y., a corpo- Application October 7, 1937, Serial No. 187,728

3 Claims.

The present invention relates to electrical insulators, and particularly to high tension insulators of the type secured to-a cross arm or other support by means of a pin or stud.

it has heretofore been the common practice, in high tension insulators of this typ to make the pin or stud as an integral flxed part of the insulator when the insulator is initially assembled at the factory. On the transmission lines on which such insulators are used, the cross arms form size but of varying sizes, requiring diflerent lengths of studs for the different sizes of cross arms. This has heretofore required the manufacturer to keep in stock each of the different sizes of insulators equipped with each of the different standard lengths of studs, thus multiplying the number of insulators to be kept on hand.

An object of the present invention is to dispense with the necessity for keeping a stock of each size of insulators equipped with each size of stud, by providing diiferent sizes of studs each of which may be applied to any of the different sizes of insulators. Thus the manufacturer need keep on hand only a supply of the diiferent sizes of insulators, without studs, and a supply of the different sizes of studs, and can supply any required size of studs along with any required size of insulators.

A further object is the provision of such an arrangement in which. the stud, when applied to the insulator, is securely locked in place without danger of accidental separation of the parts.

A further object is the provision of an insulator so designed and constructed that it may be shipped in a materially shorter or smaller crate= than that which has heretofore been necessary for an insulator of the same size.

To these and other ends the invention resides in certain improvements and combinations of parts, all as will be hereinafter more fully described, the novel features being pointed out in the claims at the end of. the specification.

In the drawing:

Fig. 1 is aside elevation of an insulator constructed in accordance with a preferred embodi- 'ment of the invention, showing it applied to a cross arm illustrated in transverse section, and

a conductor secured to the insulator;

Fig. 2 is a vertical section through the lower part of the insulator before the stud is applied thereto;

Fig, 3 is an elevation of the stud before it is applied to the insulator;

Fig. 4 is an end view of the stud, viewed from its upper end, and

Fig. 5 is a vertical section through the lower part of the insulator with the stud in place thereon.

The same reference numerals throughout the several views indicate the same parts.

In the embodiment here illustrated as a preferred example of the invention, the insulator comprises a body ll of any suitable dielectric material, such as porcelain, having any desired number of skirts or petticoats IS, the body being hollow or tubular with an interior cavity |5 in-.

tegrally closed at one end by the dielectric body. At its closed end, which is usually the upper end in use, the insulator is provided with a conductor groove I! in which a conductor IQ of a transmission line may be received, and with a tie wire groove 2|, in which a tie wire 23 may be secured.

The opposite or lower end of the insulator is closed and sealed against access of moisture by suitable means such as a rubber or rubber composition disk 25 extending across'the space l5 near its mouth, and a, metal disk 21 around the periphery of which the rubber disk extends, and a body of cement 29 serving to retain a cupshaped metal member 3| in place on the lower end of the insulator b y, the cup having an annular flange surrounding the lower end of the insulator body as in Fig. 2. Part of the surface preferably of somewhat saw-toothed shape, and

so designed as to provide sharp shoulders or abut.- ments resisting rotary movement of anything contacting with these serrations in an unscrewing direction, but affording little resistance to rotary movement in a screwing up or tightening direction.

The stud 45 for securing the insulator body to the cross arm or other support, has external screw threads 41 at its upper end for threaded engagement with the threads 4| on the cup 3|. Below these threads, thestud is provided with an outwardly extending flange 49 the upper surface "of which has an -annular series of serrations 53,

which may be of saw-toothedform similar to the serrations 43, but faced in the opposite direction, as shown in Fig. 5.

When the stud 45 is screwed into the threads 4| of the cup 3|, the serrations 53 may contact directly with the serrations 43, if desired, but it is preferred to interpose a split lock washer 55 having oflset ends 51 and 59 bent slightly out of the.

plane of the main body of washer. when the stud is screwed into the threads 4|, the serrations on the stud may slip over the end 59 of the split washer, and the end 51 of the washer may slip over the serrations 43 on the cup ll, without undue resistance. Once the stud is thoroughly tightened, the sharp or substantially vertical shoulders of the serrations 43 will be in the path of the offset end 51 of the washer 55 and will prevent this washer from turning in an unscrewing direction with respect to the cup 3 I while the end 59 of the washer will lie in the path of the sharp or substantially vertical shoulders of the serrations 53 and will prevent the stud from turning in an unscrewing direction with respect to the washer 55.

This provides means which strongly resists un screwing movement of the stud and eiiectively locks the stud in place on the cup 3|, so that once the stud has been screwed home, it becomes an integral fixed part of the insulator assembly and cannot possibly become accidentally displaced therefrom. This locking of the stud to the dielectric body is of the greatest importance, for a construction in which there was any reasonable possibility of the stud working loose, as a result of vibration or otherwise, would be too dangerous for practical use. The damage that might follow from an insulator coming off its stud and allowing the high tension transmission line to fall, can be readily imagined.

Below the flange 49, the stud 45 is provided with a suitable non-circular part which may be gripped by a wrench for the purpose of screwing the stud tightly into the cup. This non-circular part may be polygonal, or may be formed with flat spots as indicated at 6|, or of other suitable form.

The lower end of the stud is provided with externalscrew threads 63 for receiving a nut to hold the stud securely to the cross arm or other suitable support 51. If the cross arm is of wood as is commonly but not always the case, anut locking member 69 may be employed between the nut 65 and the cross arm, this locking member having a point entering the wooden cross arm to prevent the member from turning, and having another portion engaging .the nut 55 to prevent the nut from tm'ning with respect to the locking member.

The height or thicknesssof the cross arm in a vertical direction, indicated in Fig. 1 by the character H, may vary on different transmission lines, or on different parts of the same transmission line. Hence studs of different lengths are necessary. By employing the present invention, the insulator manufacturer need not make up each size or style or" insulator with each different length of stud thatmight be required, but may make up the different sizes or styles of insulators without studs, and keep on hand a supply of studs of each different length, and then ship the required length of stud with each insulator.

If the insulator is shipped without the stud screwed thereinto, it may be crated in a substantially shorter crate than is necessary if the stud is fixed to the insulator in final position, before crating, thus saving substantial crating expense. The stud may be placed in the crate alongside of the insulator, without adding at all to the length of the crate, and may be wired or otherwise secured therein. It is but the work of a moment to screw the stud tightly'into the insulator when the insulator is uncrated upon reaching the location of use. Yet when thus screwed in, the stud is anchored effectively to the insulator and cannot become accidentally removed therefrom. It is anchored just as firmly as in the prior construe--v tions where the stud or pin was initially assembled as part of the insulator before shipping it to the point'of use.

It is to be noted that in the form of insulator shown as a preferred embodiment of the invention, the insulator body remains hollow and free from any metal, except at the lower end thereof. No metal rod, core, or pin is necessary within the insulator, thus greatly improving the dielectric strength and characteristics of the insulator over those insulators in which the metal pin extends through a substantial part of the length of the insulator. While the present invention is adapted especially to insulators of the kind described, it may be applied also to various other kinds and styles of insulators.

While one embodiment of the invention has been disclosed, it is to be understood that the inventive idea may be carried out in a number of ways. This application is therefore not to be limited to the precise details described, but is intended to cover all variations and modifications thereof falling within the spirit of the invention or the scope of the appended claims.

I claim:

1. An electrical insulator including an elongated hollow body of dielectric material integrally closed at one end and having a conductor groove adjacent said closed end, means including a metal cup embracing and closing the opposite end of said body, said cup having a central portion dished inwardly and extending-partly into the interior of said dielectric body and having a screw threaded opening in a wall of said dished portion, a threaded stud for engaging a support, the threads of said stud being interengaged with the threads of said opening in said cup, and locking means preventing unscrewing of said stud from said cup, said locking means being located within said-inwardly dished portion of said cup so as not to interfere with the portion of said cup around said dished portion resting flat against a supporting surface.

2.'An electrical insulator includingan elongated upright hollow body of dielectric material integrally closed adjacent its upper end, a metal cup embracing and closing the lower end of said body, said cup having a central portion dished upwardly and extending partly into the interior of said dielectric body and to an elevation above the bottom edge of said body, said cup having a screw threaded opening in said dished portion and having an annular series of serrations around said opening, and a stud having a screw threaded upper end engaged in said threaded opening, said stud having a radially projecting circumferential flange near its upper end so placed that when said stud is screwed home in said cup, said flange is located within the dished portion of said cup and above the plane of the bottom of said cup so as not to interfere with the bottom of said cup resting flatly upon a support-.

ing arm, and an annular series of serrations formed on the upper surface of said flange on said stud, for cooperation with said serrations on said cup to resist unscrewing of said stud from said cup.

3. A construction as described in claim 2, in which a lock washer with offset teeth faced in opposite directions is interposed between said sgnt'lations on said cup and said serrations on said s u RALPH L. 

